CVE-2024-38598

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

md: fix resync softlockup when bitmap size is less than array size

Is is reported that for dm-raid10, lvextend + lvchange --syncaction will

trigger following softlockup:

kernel:watchdog: BUG: soft lockup - CPU#3 stuck for 26s! [mdX_resync:6976]

CPU: 7 PID: 3588 Comm: mdX_resync Kdump: loaded Not tainted 6.9.0-rc4-next-20240419 #1

RIP: 0010:_raw_spin_unlock_irq+0x13/0x30

Call Trace:

<TASK>

md_bitmap_start_sync+0x6b/0xf0

raid10_sync_request+0x25c/0x1b40 [raid10]

md_do_sync+0x64b/0x1020

md_thread+0xa7/0x170

kthread+0xcf/0x100

ret_from_fork+0x30/0x50

ret_from_fork_asm+0x1a/0x30

And the detailed process is as follows:

md_do_sync

j = mddev->resync_min

while (j < max_sectors)

sectors = raid10_sync_request(mddev, j, &skipped)

if (!md_bitmap_start_sync(..., &sync_blocks))

// md_bitmap_start_sync set sync_blocks to 0

return sync_blocks + sectors_skippe;

// sectors = 0;

j += sectors;

// j never c

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References